Article of manufacture and method of producing same



March 14, 1939. F. K BEZZENBERGER 2,150,671

ARTICLE OF MANUFACTURE AND METHOD OF PRODUCING SAME Filed March 19, 1937 2 Sheets-Sheet 1 CU 77A! @076 7 60 50 40 3o x41 52' M076 60 7o 60 4o 3o /0 00% Lil-3 44w;

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ARTICLE OF MANUFACTURE AND METHOD OF PRODUCING SAME Filed March 19, 1957 2 Sheets-Sheet 2 I l r INVENTOR. FEEDER/ck K- BEZZE/VBEPGEE ATTORNEYS Patented Mar. 14, 1939 UNITED STATES ARTICLE OF MANUFACTURE AND LIETHOD F PRODUCING SAME Frederick K. Bezzenbcrger, Cleveland, Ohio Application March 19, 1337, Serial No. 131,931 Claims. (01. 75-134) This invention relates to the art of producing metallic articles and more particularly to a new and improved process for producing composite metallic articles of that general type which con- 5 sists of a substantially uniform dispersion of non-metals or unalloyed metals in non-ferrous metals and alloys.

My invention rests upon the discovery that when maintained within their bi-phase temper-,-

ature range, metals and alloys may be readily mixed with one or more non-metals or non-alloy metals andthat, when maintained within that temperature range, such mixtures may readily be formed, by the application of pressure, into useful articles. When the formation is accompanied by working, the articles consist of a uniform dispersion of the non-metals or non-alloying metals throughout the metallic component, which latter is in a condition metallographically 2o equivalent to that of the same metallic component if hot worked to about the same extent.

I have found that for many, and perhaps all alloys and metals, particularly of the non-ferrous type, there is a temperature or range of tempera- 25 tures at which certain portions of the alloys or metal are in a liquid or truly molten condition while other portions are in a solid or at least semi-solid condition. For purposes of brevity, I shall call this temperature or range of tem- 30 perature the bi-phase temperature or temperature range, and by this term I mean that temperature or temperature range at which, under normal conditions, the alloy or metal consists of the phases, liquid and solid, in equilibrium. The bi-phase temperature or temperature range being related to the solidification range, varies for each metal and alloy, and the extent of such range is a determining factor in the operation of my process, as I shall describe. I, have found 40 that when an alloy or metal is maintained within its bi-phase temperature range, it possesses certain characteristics which permit the practice of the process of this invention. Thus, when an alloy or metal is maintained within the lower portion of its bi-phase temperature range, however short such range may be, it is friable and brittle, and accordingly, if a finely divided solid such as a non-metal, for example, capable of presenting the recementing of the resulting particles be present, such alloy or metal can easily be ground or comminuted, and thus have thoroughly and uniformly mixed with it the solid which prevents the receinenting of the particles.

Such comminution or mixing is attended by the continued presence of the liquid phase, and

I have found that the resulting more or less granular mixture, still maintained within the biphase temperature range", or cooled and subsequently reheated to the bi-phase temperature range, may be formed into useful articles by the 5 application of pressure with attendant working of the metal or relative inte'rgranular movement of the metal grains.

It will be clear that in such forming operation, the resistance to recementization of the particles 10 is broken down by the inter-particle movement incident to the forming operation, and that the final efiect is a metallic body, containing a dispersion of the non-metal within the alloy or metal, the previously existing particles of the 15 solid phase of which have been recemented by the soidiflcation upon cooling, of the previously existing liquid phase.

I have'further found that when an alloy having a relatively long bi-phase temperature range is maintained within the upper portion of that range, it becomes more or less plastic or semi-fluid, and that, while in this condition, finely divided solids such as non-metals and nonalloying metals, even though having specific gravity diflering widely from that-of the alloy, may readily be uniformly mixed with it, and the resulting mixture may be formed into useful shapes by the application of pressure.

While I prefer, as a matter of economy to proceed in either of the two manners I have described, I have found that I may use comminuted or finely divided metals as starting materials and mix therewith, while at room temperature, such finely divided solids, that is non-metals or nonalloying metals, as may be desired in the finished article and subsequently raise the temperature to within the bi-phase temperature range, whereupon useiul articles may be produced by the application of pressure, with the results I have described.

It will now be clear that the essence of my invention lies in the provision of a process whereby intimate mixtures of solids, as finely divided non-metalsor non-alloying metals, with metals or alloys may be made, and whereby such mixtures may be fabricated into useful articles by the application of pressure, while maintaining a high degree of dispersion of the iormer in the latter. When pressure is applied but no pronounced intergranular movement of the particles takes place, the metallic component of the resulting article will be metallographically substantially identical with that of a cast alloy of equal composition, but when thepressure is accompanied by a marked intergranular movement, the metallic component of the resultant article is metallographically substantially identical with a hot worked alloy of equal composition.

In a general sense, it may be said that the solid phase particles have, during my process, been separated from each other, finely divided solid material has been introduced therebetween, and

they have been recemented to each other by the same component, namely, the liquid phase, which held them together in their original state.

It will therefore be clear that the properties of the article as a whole will be substantially those of the original metal or alloy, due allowance being made for the eifect of the non-metal or non-alloying metal present.

The process of this invention, which I have described generally and which I shall describe in detail, may be applied to a wide variety of metals and alloys; bronzes, aluminum alloys and lead alloys being typical examples.

I can by this means incorporate in metals and alloys a fine and uniform dispersion of nonmetals, such as graphite, silica, carborundum, as examples, in amounts up to as much as 50% of the weight of the non-metal. I can additionally by this means incorporate inmetals and alloys fine and uniform dispersions of non-alloying metals, such for example as finely divided copper in lead-tin alloys.

The finely divided solids which may be used in this process include any finely divided nonmetallic or non-alloying metallic substance which is non-combustible, non-volatile and preferably non-fusible at the bi-phase temperature" or temperature range of the metal or alloy with which such substance is to be mixed. Graphite and mica are illustrative of such solids which may be used when non-frictional or lubricating characteristics are desired in the resulting article. Carborundum and silica are likewise illustrative of solids which may be used when frictional characteristics are desired in the resulting article.

The resulting composite metallic articles may be produced economically, and depending upon their character and components, are useful for a wide variety of purposes, such as bearings, friction articles, such as brake and clutch linings, trolley shoes, piston rings, pistons, electrical brushes, etc.

Composite articles made by the present process, including the step of plastic working under pressure, are apparently made up of metallic particles or grains which were in the solid state during the mixing operation, finely divided solid ingredients WhlCh are disposed between such grains and metallic material which existed in the liquid state during the mixing operation but which in a completed article is united to the said grains .and holds them together and partly surrounds the said solid ingredients. Such an article consists of a substantially continuous metallic net work in which the solid ingredients are embedded and held fixed in their uniformly distributed positions and such net work has apparently about the same physical properties as the same metallic composition would have if it had been hot worked to about the same extent, due allowance being made for the difference in volume of the metallic composition due to the amount of solid ingredients which are present.

The "bi-phase temperature range for any metal or alloy may readily be determined. in a practical way, either independently of, or pre!- erably with reference to, the constitution diagram for the particular alloys desired. Such diagrams, found in text boolns, are available for most binary and many ternary alloys, and in addition to supplying information as to the biphase temperature range of a particular desired alloy, also serve as a guide in the choice of alloys best adapted to my process.

Those skilled in the art will recognize that pure metals and eutectic alloys exhibit practically no bi-phase temperature range, while commercial metals, by reason of the presence of certain impurities, have an appreciable "bi-phase temperature range", while certain alloys have very long bi-phase temperature ranges, amounting to as much as 200 or 300 F. in some cases.

Inthe practice of my process I prefer, where possible, to use an alloy having a "bi-phase temperature range" of at least 10 F., since the dimculty of maintaining an elevated temperature within closer limits, while possible, presents an added problem which can usually be avoided by modifying the composition of the alloy to a slight extent, and thus providing a range of that magnitude.

In the drawings accompanying and forming a part of this application:

Figure 1 is a constitutional diagram tor the copper-tin alloys;

Figure 2 is a constitutional diagram'i'or the aluminum-silicon alloys;

Figure 3 is a constitutional diagram for the lead-tin alloys;

Figure 4 is a longitudinal, sectional view, partly in elevation, taken on line 4-4 of Figure 5, showing one form of apparatus with which the present invention may be practiced.

Figure 5 is a transverse sectional view taken on line 5-5 of Figure 4;

Figure 6 is a horizontal sectional view taken on line 6--6 of Figure 4; and

Figure 7 is a fragmentary view of an extrusion nozzle extension of tube 9 of Figure 4.

Figures 1, 2 and 3 are constitutional diagrams for classes of alloys which may be used for the metallic component of the composite articles to be produced by my process, it being understood that many other diagrams are readily available in text books of metallography. These diagrams may serve as guides in the choice of an alloy from any particular class, and additionally, indicate the bi-phase temperature range of such alloys and its extent.

In Figure 1, which is the constitutional diagram for the copper-tin alloys (as given by Hoyt on page 117 in his book Applied Metallography" published in 1921 by McGraw-Hill Book Company .of New York) the various temperatures along the vertical side of the diagram apply to copper-tin compositions ranging from 100% of copper at the left hand side of the diagram to 100% tin at the right hand side of the diagram. By relating these figures to the curves, the condition of the particular alloy in question at certain temperatures may readily be determined. Curve A is known as the liquidus, by which is meant a line drawn through a series of points, each of which represents the minimum temperature at which the corresponding alloy is completely and entirely molten, that is, in liquid state. Curve B is the "solidus, by which is meant a line drawn through a series of points, each of which represents the maximum temperature at which the correspondingly alloy is completely and entirely frozen, that is, in solid state.

, 4 2,160,671 Between curves A and B, the alloy is partly liquid and partly solid, by which I mean that in this range it consists of a heterogeneous mass of liquid dispersed through solids, or solid particles dispersed through liquids. This condition arises from the unequal melting points of the various portions of the alloy and it will therefore be clear that for any alloy the relative proportion of liquid and solid phases which are in equilibrium with each other is dependent upon the temperature, the higher the temperature the higher the proportion of the liquid phase.

The manner in which these constitutional diagrams may be used will now be clear. If, for example, I wish to make a composite article whose base metallic compound shall be a bronze, I refer to Figure 1, and find that within the high copper, low tin alloys, an alloy consisting of 92% copper and 8% tin, has a liquidus temperature, curve A, of about 1840 F. and a solidus temperature of 1570 F., and that accordingly, the liquidus-solidus range is the difference between these two temperatures, that is,-270 F. From this information I know that such alloy, characterized by such long range, is particularly well adapted to my process, and that the bi-phase temperature rangef lies within those limits.

In order to define closely the operating temperature best suited to the production of the particular composition desired, I next melt a small quantity of the 92% copper, 8% tin alloy, and while observing its temperature, as by meansof a pyrometer, I permit it-to cool, with continued observation of its physical properties, as by working it with a tool, until the mostdesired state of plasticity or friability to permit mixing therewith the non-metal, for example, is attained. I have found that such condition usually lies within a range which is about 10% below the liquidus, and about 10% above the solidus, when such percentages are calculated against the total liquidussolidus range, as taken from the diagram. This range I have termed the bi-phase temperature range, and in the present example, would be 1813 F. 'to 1597" F.

Similarly, in Figure 2, which is the constitutional diagram for the aluminum-silicon alloys (as given by Guillet and Portevin, on page 213 of the publication entitled Metallography and Macrography, published by the McGraw-Hill Book Co. of New York), the line C is the liquidus and the line D is the solidus, and accordingly the diagram serves as a guide in the choice of an aluminum-silicon alloy best suited to my purpose for the metallic constituent of my composite metallic articles when used in the manner I have described.

Figure 3 is the constitutional diagram 'for the lead-tin alloys (Hoyt, supra, p. 49) and on this diagram the line E is the liquidus and the line F the solidus, andthis diagram provides another example of the use of such diagrams in the practice of my process. I

Figure 2 provides a clear example of an alloy having practically no liquidus-solidus range, this alloy being of the composition Al-10% silicon, according to this diagram. Such compositions are called eutectic alloys, and like pure metals, are preferably avoided in the practice of my process, although they may be used, provided temperature control within the narrow limit required is provided.

Similarly, in Figure 3, which shows a constitu tional diagram for lead-tin alloys (Hoyt, supra, p. 49) the temperature ranges given along the one wall of the box 6.

vertical side of the diagram apply to alloys ranging from of lead at the left side of the diagram to 100% of tin at the right side thereof. The solidus-liquidus temperature ranges of alloys of this diagram and the bi-phase temperature ranges are between lines E and F.

In Figures 4 to 6 are illustrated one form of simple apparatus with which the present invention may be practiced. In these figures, a base I supports a heat-insulating structure 2 provided with a removable cover 3 having openings 4 and 4a therethrough, the latter having a removable cover 4b and being large enough to permit raw materials to be passed therethrough. The walls 2 and cover 3 form a heating chamber 5 in which is supported a mixing box 6, preferably composed of metal covered at the top by cover 3, and having a bottom discharge opening I communicating with a cylindrical open ended compression chamber 8. The latter chamber is formed in an elongated tubular extension 9 of box 6 and is provided at either end with plungers H] which may be actuated toward and away from each other by any suitable means such as the racks and pin- I ions II and I2. Within the box 6 is disposed a manually operable valve 13 shaped to seat in and close opening I and to prevent discharge of material from the interior of box 6 into chamber 8. This valve is attached to a rod M which extends through opening 4 in cover 3, through a' hearing or guide I 5 on the cover, and is connected to lever I 6. by which it may be lifted or lowered.

Two shafts l1 extend through one wall 2 and These shafts are supported in bearings I8 and IS in said walls respectively, and at their outer ends are supported by bearings 20, and at their inner ends by bearings 2| carried by a wall or box 6. These shafts I! carry gears 22, one of which meshes with a driving gear 23 and by which they may be rotated in opposite directions. Within the box 6 the shafts I! carry blades 24 which are preferably fiat, narrow and triangular shaped in elevation, as is shown in Figures 4 and 6, the blades of the two shafts being staggered relatively, so that they will not strike one another when the shafts are rotating. Preferably, the shafts are so geared that they do not rotate at the same speed. The blades 24 adjacent to the valve rod M are cut away to clear the rod during rotationyas is best shown in Figure 6.

' The blades 24, when rotating, serve to mix thoroughly the above mentioned solids with the metallic material as its bi-phase temperature, and also assist in discharging the mixed material through opening I when valve I3 is lifted.

Suitable heating elements 25 are provided on the exterior of box 6 to heat the box and its contents too, and maintain it at the desired temperature. A pyrometer is shown at 26. Pipe 21' serves as a means of introducing gas into box 6, such as hydrogen, for example, if a non-oxidizing atmosphere is to be maintained to prevent oxidation of the metal during treatment.

In order to provide a clearunderstanding of my process, I shall describe in detail one specific example, it being understood that it may be applied to a wide variety of composite metallic articles, varying from each other in the character of the metallic, the character of the non-metallic or non-alloying component or components, where more than one is used, and in the proportion of the former to the latter, all as I have described. I shall use in this example the 92% copper, 8% tin alloys whose choice and temperature characteristics I have described, and I shall describe the treatment of this alloy for the production of a composite metallic article containing 5% by weight of graphite.

I first secure or prepare a quantity of such a1- loy and, in a typical crucible or conventional type, I raise its temperature by any suitable means to a point above its liquidus, that is 1840, and thus bring it to the condition in which it is entirely molten. Simultaneously, I raise the temperature of the mixing box 6 to the bi-phase temperature range of the alloy, in the present example to a point between 1813 F. and 1597 F. preferably, in the present instance, to about 1650 F., at which point I have found the particular operation being described to proceed most satisfactorily.

As the temperature of the alloy falls to that of the box, in this case about 1650 F., it becomes more or less pasty or plastic, and the combined operation of the mixing blades 24, at this preferred temperature, thoroughly and uniformly mixes the graphite into the alloy, resulting in a pasty or semi-granular mass, in which the graphite occurs as adispersicn in the alloy. While still maintaining the temperature at the preferred 1650 F. for this case, and with the continued rotation of the mixing blades, and with the plungers H) in the approximate position shown in Figure 4, to provide compression chamber 8, I now raise the valve l3, thus permitting a definite amount of such mixed mass to flow into the chamber. I now close the valve l3, and by means of the racks and pinions H and I2, force the two plungers toward each other, thus exerting high pressure-on the mass contained in the chamber 8. I next remove one plunger from the tubular extension 9, and by suitable movement of the other,

1 eject the resulting article from the open end of the chamber 8, whereupon slight cooling effects solidification.

The operation which I have described results in the formation of a slug or billet and may be repeated as often as is permitted by the relation of its weight to the weight of material in the mixing box.

It will be clear that the simple arrangement which I have described is subject to wide variation in both operation and design. For example, I may omit one plunger [0 and change the shape of one end oftube 9 into that shown at 28 in Figure 7 where the outlet opening 29 has been reduced in area and altered from a disc to a rectangle. The plunger ID will compress the mixture in chamber 8 and extrude it through outlet 29. I

It will be obvious that the shape of the outletopening 29 may take any one of a wide variety of shapes depending on the shape of the article which is desired. Thus, rods of various cross sectional shapes and sizes, strips and the like may be made. Tubes can also be made by fixing a plug in and partly filling the outlet opening. Such plugs are common, in metal piercing apparatus and no further description thereof here is therefore thought to be necessary.

It will be understood that the illustrated apparatus is but one example of widely varied equipment which may be used for carrying out my invention, and those skilled in the art will recognize that any device capable of mixing the components in the general manner I have described, and subsequently removing the resulting mixture either in finished form or in objects or conditions for further treatment, may be used.

While I may use the apparatus described with reference to Figures 4, 5, 6 and 7 for the direct production of finished articles in one operation, I have found that it is generally more advantageous to proceed first to the formation of slugs or billets, as I have described, and subsequently to reheat such slugs or billets for the formation of finished articles. Thus, I have found that if I permit the slugs or billets to cool, and subsequently reheat them to the biphase temperature range and place them within suitable dies, also preferably at the same temperature, I may very easily extrude them into various shapes, such as rods, wire, tubes or sheets. Additionally, with suitable equipment related to suitable dies, I may very economically form shapes of various kinds from my composite metallic mixtures, while maintained' within their bi-phase temperature range, an example of such being a graphited-aluminum alloy piston. The various operations which may be performed on my composite metallic mixtures or primary articles formed therefrom will be clear to those skilled in the art upon recognizing that such mixtures within their bi-phase temperature range consist of a suspension of particles of the solid phase, and particles of the non-metal or non-alloying metals, suspended in or dispersed throughout a liquid phase which readily permits their movement with reference to each other, and this permits their readyconformance, under pressure, to a surrounding contour. a die for example.

As an alternative to the process I have described, I may continue the mixing operation while permitting the temperature to fall g: adually below the solidus for the metal or alloy under treatment, in which case I have found the resulting mass to consist of finely divided particles of the metallic compound mixed with the agent, such as non-metal, which prevents their recementation to each other. Such mixtures may be used directly or may have the agent which prevents recementation removed from them, either wholly or in part, as by sifting, or may have subsequently mixed therewith one or more non-metals or non-alloying metals, and such mixtures may be placed within a die and reheated to the bi-phase temperature range", whereupon they may be worked into finished shapes by the application of pressure as I have described.

Under certain conditions where it is not desired to add any solid ingredients to the mixture before it is reheated and where it is desirable not to lose appreciable amounts of the solid ingre'dients previously -mixed with the metallic constituents as described in the preceding paragraph, the mixing operation should be interrupted before the mixture has reached the temperature at which the mixture takes the form of finely divided particles. In other words, the mixture exhibits a tendency to separate into particles as the temperature drops during the mix ing operation. When these particles first form they are fairly large in size but as the mixing and cooling continues they become smaller and smaller. The solid ingredients may readily be separated from the metallic ingredients when the particles are quite small and hence it is preferable to interrupt the mixing operation while the particles are fairly large in size to avoid the loss of the solid ingredients.

While I have described more or less completely the practicing of my invention on a. copper-tin alloy it is not to be understood that my invention is limited thereto. As a matter of fact it can heating the resulting granular mixture to a tembe practiced on practically all non-ferrous alloys having a bi-phase temperature range of at least about 10 F. and it may be practiced with somewhat greater dimculty on non-ferrous eutectic alloys and non-ferrous metals provided there is a temperature range of approximately 10' F. between the completely solid state and the completely liquid state and provided further that the temperature of such metallic material can be maintained within that range during the mixing operation.

I have practiced the present invention on various non-ferrous alloys having appreciable biphase temperature ranges. For example, I have uniformly mixed about 36% of graphite by weight with a commercial alloy containing approximately 95% of aluminum and of silicon and have obtained extruded articles from such mixture in which the metal apparently possessed greater ductility than the alloy itself normally possessed and in which the physical properties of the metal were about 60% of those possessed by the alloy used as a starting material. The difference in physical properties was traceable to the presence of the large amount of graphite.

The term finely divided solid" and similar expressions appearing hereinabove and including non-metallic as well as metals is intended to include non-metallic substances such as waxes and the like which have a melting point above that of the metal or alloy with which'it is to be mixed. For example, Carnauba wax melts at a higher temperature than certain non-ferrous metals with which it might be mixed by the present process. It will thus be in a condition suitable for use by this invention, is includable within the contemplated scope of the invention and moreover would confer lubricating properties on metals or alloys with which, it is mixed by this invention.

Having thus described my invention so that those skilled in the art may be able to practice the same, what I desire to secure by Letters Patent is defined in what is claimed.

I claim:

1. The process of producing composite metallic articles which consists in mixing finely divided non-alloying materials with non-ferrous metallic materials while at a temperature within the bi-phase temperature range of the latter, continuing the mixing while permitting the temperature of the mixture to fall to a temperature below the solidus of the metallic material, re-

perature within its bi-phase temperature range, and forming the mixture into articles by the application of pressure.

2. The method of making metallic articles, which includes the steps of heating non-ferrous metallic material to its bi-phase" temperature and, while maintaining it at such temperature, mixing uniformly therewith finely divided solids, continuing the mixing while cooling the mixture, interrupting the mixing before the temperature reaches a point at which the solids will largely separate from the metallic materialrthereby obtaining a mixture in the form of particles, reheating the mixture in such particle form to the bi-phase temperature and pressing it into an article.

3. The process of producing composite metallic articles which consists in mixing finely divided non-alloying materials with non-ferrous metallic materials while at a temperature within the bi-phase temperature range of the latter, forming the resulting mixture into primary articles, reheating the primary articles to a temperature within such bi-phase temperature range and reforming them, by plastic deformation effected by the application of pressure, into finished articles.

4. A method of making metallic articles, which consists of the steps of heating non-ferrous metallic material, which is to remain as a component in the final article being made, to its biphase temperature and, while maintaining it at such temperature, mixing uniformly therewith a substantial percentage of finely divided nonmetallic solid material and pressing the mixture into an article containing substantially the same percentage of said non-metallic solid material as was present in the said mixture.

5. As an. article of manufacture, a solid article having a hot-worked metallic structure and comprising a non-ferrous metallic matrix having substantially uniformly dispersed therein a finely divided non-metallic material, said article having been produced by heating non-ferrous metallic material, which is to become a component oi the finished product, to its bi-phase temperature range and, while maintaining it at such temperature, mixing substantially uniformly therewith finely divided non-metallic material and pressing the mixture into said article.

FREDERICK K. IBEZZENBERGER. 

